The main question in your case: does your manuscript is published in print or not? If so - there is nothing to do, because you've had possibility to make final corrections to your manuscript and missed it. If not - you have to write explanation and correct name of co-author to the editor and online administrator in hope they'll make appropriate changes.

It was published with the correct spelling of the co-author. Researchgate messed it up by changing both first name and gender (from Kevin to Karla)

@H.A. Tillmann Hein, To change the authors in RG, open the paper and there is a 'more' option at far right at the top. Click it and a drop down menu opens which has 'edut'. Click this and it directs you to the paper's details which are editable which includes author names. However, if you made changes to author list recently, you have to wait for some time to revise the author details.